JP3771478B2

JP3771478B2 - Method and apparatus for treating incineration ash

Info

Publication number: JP3771478B2
Application number: JP2001329055A
Authority: JP
Inventors: 芳忠角田; 孝弘増田; 達地崎; 大藏國井
Original assignee: Takuma KK; Chisaki Co Ltd
Current assignee: Takuma KK; Chisaki Co Ltd
Priority date: 2001-10-26
Filing date: 2001-10-26
Publication date: 2006-04-26
Anticipated expiration: 2021-10-26
Also published as: JP2003126802A

Description

【０００１】
【発明の属する技術分野】
本発明は、都市ごみや産業廃棄物等を焼却した際に生じる焼却灰（集じん飛灰等を含む）の処理方法、及び当該処理に特に好適な焼却灰の処理装置に関し、焼却灰に含まれる有害な有機塩素化合物を低減する技術として有用である。
【０００２】
【従来の技術】
人体に有害な有機塩素化合物、例えば、ＰＣＤＤ（ポリ塩素化ジベンゾダイオキシン）、ＰＣＤＦ（ポリ塩素化ジベンゾフラン）等のような高毒性の芳香族系塩素化合物は、ごみ焼却の際の二次生成物として生成され、環境を汚染することが知られている（Ｋ．Ｏｌｉｅｅｔａｌ，Ｃｈｅｍｏｓｐｈｅｒｅ，６，４５５（１９７７）等）。そして、当該有機塩素化合物は、ごみ焼却処理施設に付設されている電気集塵器（ＥＰ）およびその他のばいじん除去装置から排出される焼却灰中に混入することも指摘されている。焼却灰にＰＣＤＤやＰＣＤＦ等が含有されていると、その焼却灰を、例えば埋め立てに用いた場合、浸出水等を経て人体や動・植物に還流し、悪影響を及ぼす危険がある。
【０００３】
このような焼却灰中の有機塩素化合物を低減する装置としては、例えば特開平３−２７５１８４号公報のような、スクリュー回転軸を有する横型の焼却灰加熱脱塩素化装置が知られている。図５は、このような従来の加熱脱塩素化処理装置の説明図である。この装置は、水平方向に長い装置本体５１と、該装置本体５１の軸方向に間隔をおいて設けられた焼却灰Ａの投入口５２および処理物の排出口５３と、前記装置本体５１内に設けられた回転軸５６と、該回転軸５６に固着された導入部スクリュー５４、攪拌羽根５７および排出部スクリュー５５と、前記装置本体５１の表面に配置されたバンドヒータ５８とから主として構成されている。被処理物である焼却灰Ａは、焼却灰投入口５２から装置本体５１に投入され、回転軸５６の導入部スクリュー５４の作用を受けて排出口５３方向に移動し、この間に攪拌羽根５７によって攪拌・混合されるとともにバンドヒータ５８によって、３００℃以上、例えば４００℃に加熱され、該焼却灰Ａに含まれる有機塩素化合物が分解する。有機塩素化合物が分解除去された処理物は排出口５３から装置外に抜き出される。
【０００４】
また、特開平６−３１２１７２号公報には、常時安定して高い脱塩素率を得ることができる焼却灰の処理方法および装置を提供すべく、ごみ焼却施設から回収した焼却灰を加熱装置内を移動させながら加熱して該焼却灰に含まれる有機塩素化合物を分解する焼却灰の処理方法において、前記焼却灰の移動方向とは逆向きの空気流を形成して加熱装置内をパージしながら焼却灰を３００℃以上に加熱する方法が開示されている。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記公報のような加熱装置を使用する場合、原料である焼却灰の予熱及び処理物の冷却等が必要となり、エネルギー的に不利となり設備全体が複雑化、大型化し易い。また、空気流下で処理物を冷却する際に、温度条件等を適切に制御しないと、分解生成物からダイオキシン類が再合成されるという問題がある。
【０００６】
一方、特開２００１−２５７３５号公報には、４００〜５５０℃で酸素存在下で灰中のダイオキシン類を分解する方法が開示されているが、このような高温で焼却灰を加熱処理する場合、上記公報のような処理装置や一般の回転型加熱炉では、処理物の炉壁への固着や攪拌の困難性が問題となり易く、メンテナンス面や処理効率の点で問題が生じ易い。即ち、一般的な集じん飛灰では塩化カルシウムの含有率が高く、更にカドミウム、鉛、亜鉛などを含有するため、飛灰の融点が加熱温度より低くなり、処理物の炉壁への固着などが生じ易くなる。
【０００７】
そこで、本発明の目的は、エネルギー的に有利で省スペース化が可能で、しかもダイオキシン類の再合成が行われにくい焼却灰の処理方法を提供することにある。また、この処理方法に好適に使用でき、しかも処理物の炉壁への固着が生じにくく、処理物等の攪拌も良好に行える焼却灰の処理装置を提供することにある。
【０００８】
【課題を解決するための手段】
本発明者らは、上記目的を達成すべく、加熱装置内で熱交換により焼却灰を予熱と処理物の冷却を行うことに着想し、その場合でも通常より高温で加熱処理を行うことにより処理物の冷却時におけるダイオキシン類の再合成が起こりにくいことを見出し、本発明を完成するに至った。
【０００９】
即ち、本発明の焼却灰の処理方法は、加熱装置内で焼却灰を移動させながら加熱してその焼却灰に含まれる有機塩素化合物を分解する焼却灰の処理方法において、伝熱材で仕切られた被処理物の往路と復路を備えており、内筒と外筒の間に前記被処理物の往路を備え、その内筒の内部に前記復路を備える横型回転加熱装置であり、その外筒と内筒とを異なる速度で回転させて、外筒内面に付着する処理物を内筒から立設する羽根で掻きとる加熱装置を用いて、その往路の前段側の領域で処理物との熱交換により焼却灰を予熱した後、その焼却灰を前記往路の後段側及び前記復路の前段側の何れかの領域で４００〜５００℃にて加熱し、次いでその処理物を前記復路の後段側の領域で焼却灰との熱交換により冷却することを特徴とする。
【００１１】
また、前記復路の後段側から前記往路の前段側へと、空気もしくは不活性ガス又はそれらの混合ガスを流通させながら処理を行うことが好ましい。
【００１２】
一方、本発明の焼却灰の処理装置は、一端に焼却灰の導入部を有し他端が閉鎖された回転軸線がほぼ水平な外筒と、前記他端の近傍に開口部を有し他の端部に処理物の排出部を有する前記外筒と略同一の回転軸線にて相対回転可能な内筒と、前記外筒の他端側の外周近傍に配置された加熱手段と、前記外筒と前記内筒とを異なる速度で回転可能な回転駆動手段とを備える焼却灰の処理装置であって、前記内筒は、その外周面から前記外筒の内周面近傍まで立設しつつ軸線方向に沿って延びる複数の仕切羽根と、その仕切羽根で区分された複数の軸線方向空間の軸線方向の連通を許容しつつ軸線方向に対して傾斜して前記開口部近傍まで配設される複数のガイド羽根とを有し、そのガイド羽根の傾斜方向を前記複数の軸線方向空間について略回転対称として前記回転駆動手段により導入した焼却灰を他端側へ移送可能とし、前記内筒の内部には、前記開口部から導入した処理物を前記排出部へと移送する移送手段を有する。
【００１３】
上記において、前記移送手段は、前記内筒の内部空間を複数に仕切る仕切壁と、その仕切壁で区分された複数の内部空間の軸線方向の連通を許容しつつ軸線方向に対して傾斜して配設される複数のガイド板とを有し、そのガイド板の傾斜方向を前記複数の内部空間について略回転対称として前記内筒の回転により前記開口部より導入した処理物を前記排出部側へ移送可能とすることが好ましい。
【００１４】
［作用効果］
本発明の焼却灰の処理方法によると、伝熱材で仕切られた被処理物の往路と復路を備える加熱装置を用いて、その往路の前段側の領域で処理物との熱交換により焼却灰を予熱した後、その焼却灰を前記往路の後段側及び前記復路の前段側の何れかの領域で加熱処理し、次いでその処理物を前記復路の後段側の領域で焼却灰との熱交換により冷却するため、原料である焼却灰の予熱及び処理物の冷却等が殆ど不要となる。また、加熱処理を４００〜５００℃で行うため、実施例の結果が示すように、処理物が冷却時に徐冷されてもダイオキシン類の再合成が起こりにくくなる。その結果、エネルギー的に有利で省スペース化が可能で、しかもダイオキシン類の再合成が行われにくい焼却灰の処理方法を提供することができる。
【００１５】
前記加熱装置が、内筒と外筒の間に前記被処理物の往路を備え、その内筒の内部に前記復路を備える横型回転加熱装置であり、その外筒と内筒とを異なる速度で回転させて、外筒内面に付着する処理物を内筒から立設する羽根で掻きとる場合、内筒内部の復路を移動する処理物の熱がその周囲の往路を移動する焼却灰に伝熱する際に熱損失が少なく、効率良く焼却灰の予熱と処理物の冷却を行うことができる。また、外筒内面に付着する処理物を内筒から立設する羽根で掻きとることにより、処理物の固着の問題を解消することができる。
【００１６】
前記復路の後段側から前記往路の前段側へと、空気もしくは不活性ガス又はそれらの混合ガスを流通させながら処理を行う場合、発生する金属塩化物の微量成分が、高温状態の処理物と接触する機会が少なくなるため、その凝縮による融点降下を引き起こしにくくなり、処理物の装置壁面への固着が生じにくくなる。
【００１７】
一方、本発明の焼却灰の処理装置によると、内筒の外周面から外筒の内周面近傍まで立設しつつ軸線方向に沿って延びる複数の仕切羽根と、その仕切羽根で区分された複数の軸線方向空間の軸線方向の連通を許容しつつ軸線方向に対して傾斜して前記開口部近傍まで配設される複数のガイド羽根とを有し、そのガイド羽根の傾斜方向を前記複数の軸線方向空間について略回転対称としてあるため、回転駆動手段により導入した焼却灰を攪拌・転動させながら他端側へ移送できる。そして、外筒の他端側の外周近傍には加熱手段が配置されているため、外筒の他端側やその近傍の内筒内部で、焼却灰に含まれる有機塩素化合物を分解処理することができる。更に内筒の内部には、前記開口部から導入した処理物を前記排出部へと移送する移送手段を有するため、排出部側へと移送される高温の処理物と原料焼却灰との熱交換を内筒を介して効率良く行うことができる。更に、外筒の内周面近傍まで立設する仕切羽根を表面に有する内筒が、外筒と相対回転可能であり、両者を異なる速度で回転可能な回転駆動手段を備えるため、処理物の付着が問題となり易い外筒の内周面から仕切羽根で固着物を好適に掻きとることができる。その結果、本発明の処理方法に好適に使用でき、しかも処理物の炉壁への固着が生じにくく、処理物等の攪拌も良好に行える焼却灰の処理装置を提供することができる。
【００１８】
前記移送手段は、前記内筒の内部空間を複数に仕切る仕切壁と、その仕切壁で区分された複数の内部空間の軸線方向の連通を許容しつつ軸線方向に対して傾斜して配設される複数のガイド板とを有し、そのガイド板の傾斜方向を前記複数の内部空間について略回転対称として前記内筒の回転により前記開口部より導入した処理物を前記排出部側へ移送可能とする場合、仕切壁とガイド板により内筒を回転させるだけで、攪拌・転動させながら処理物の排出部側への移送が可能となる。従って、内筒の内部に別個に回転体やその駆動手段を別途設ける必要がなくなり、メンテナンス性や省スペース性等をより高めることができる。
【００１９】
【発明の実施の形態】
以下、本発明の実施の形態について、図面を参照しながら説明する。図１は、本発明の処理装置の一例の概略構成図を示すものである。なお、図中の破線はガスの流れを示し、実線は焼却灰等の固体の流れを示している。
【００２０】
本発明の焼却灰の処理方法は、伝熱材で仕切られた被処理物の往路と復路を備える加熱装置を用いて、加熱装置内で焼却灰を移動させながら加熱してその焼却灰に含まれる有機塩素化合物を分解するものである。本実施形態では、図１に示すように、加熱装置１０が、内筒２０と外筒１１の間に被処理物の往路を備え、その内筒２０の内部に処理物の復路を備える横型回転加熱装置であり、復路の後段側から往路の前段側へと、空気等のガスを流通させながら処理を行う例を示す。
【００２１】
本発明の処理方法では、まず往路の前段側の領域で処理物との熱交換により焼却灰を予熱する。用いられる焼却灰としては、都市ごみなどの一般廃棄物や産業廃棄物等を焼却した際に生じる焼却灰（集じん飛灰を含む）が使用できる。焼却灰は、例えば貯留ホッパ１に貯留され、定量切出装置によって所定量が加熱装置１０の導入口１２ａから供給される。供給された焼却灰は、供給管１２を外筒１１側へと移動して外筒１１の導入部１１ａを経て更に外筒１１の他端側へ移動する。このような往路の前段側の領域で、内筒２０の内部を移動する処理物と熱交換させることにより、焼却灰を予熱することができる。なお、熱交換を行う領域は保温材１３で被覆してもよい。
【００２２】
次いで、その焼却灰を前記往路の後段側及び前記復路の前段側の何れかの領域で４００〜５００℃にて加熱する。当該加熱処理によりダイオキシン類の分解率を９５％以上とすることも可能である。加熱温度が４００℃未満では、処理物が冷却時に徐冷される際にダイオキシン類の再合成が起こり易くなる。また、５００℃を超えると、処理物の融解や固着等が起こり易く、エネルギー的にも不利になり易い。
【００２３】
加熱は外筒１１の外周近傍に配置された加熱手段１４により行うことができる。加熱手段１４としては電気ヒータ、燃焼型ヒータ、ガス供給ヒータなどが使用できるが、設備全体を簡易化、小型化する上で電気ヒータが好ましい。また、加熱手段１４の形成する部分の周囲にも、保温材１５を設けるのが好ましい。
【００２４】
焼却灰は、加熱手段１４により加熱されながら外筒１１の他端側へ移動した後、内筒２０の開口部２１から内部へ移動され、更に加熱されながら内筒２０の排出部２２側へと移動する。
【００２５】
加熱後の処理物は復路の後段側の領域で焼却灰との熱交換により冷却される。熱交換による焼却灰の予熱及び処理物の冷却は、原料焼却灰と排出処理物との温度差が２００℃以内となるのが好ましく、１００℃以内となるのが更に好ましい。また、冷却後の排出処理物の温度が２５０℃以下となるのが好ましく、２００℃以下となるのがより好ましい。熱交換される熱量は、処理量、滞留時間、伝熱面積等によって決定することができる。
【００２６】
本実施形態では、内筒２０が往路と復路を仕切る伝熱材となるが、このような伝熱材としては、金属材料、セラミックスなどが使用でき、特に加工性の面から金属材料が好ましい。また、内筒２０の外周面又は内周面に形成される攪拌羽根等も伝熱機能を有するため、同様の伝熱材で構成されるのが好ましい。
【００２７】
予冷後の処理物は、内筒２０の排出部２２から排出される。内筒２０から排出された処理物は、一端貯留された後又は連続的に系外に排出されるが、本発明では、十分な冷却が行えるため、付加的な冷却装置を不要にすることも可能である。また、条件にもよるが、従来の熱交換を行わない焼却灰の処理装置と比較してエネルギー消費量（例えば消費電力）を１／２〜１／３とすることも可能である。本発明の処理方法における焼却灰の温度プロフィールとしては、例えば加熱手段１４の設定温度を５００℃にする場合、外筒１１の導入部１１ａにおける焼却灰が約９０℃、外筒１１の加熱手段１４内側の直前で約２３０℃、内筒２０の開口部２１近傍で約４３０℃、内筒２０の加熱手段１４内方の直後で約３３０℃、導入部１１ａ近傍の内筒２０内側で約１２０℃である。なお、本発明の処理方法によると、例えば１００〜１０００ｋｇの焼却灰を処理することができる。
【００２８】
本実施形態では、焼却灰の復路の後段側から往路の前段側へと、空気もしくは不活性ガス又はそれらの混合ガスを流通させながら処理を行う。流通ガスとしては、コスト等の点から空気が最も好ましい。
【００２９】
流通ガスの方向は逆方向でもよいが、前述したように発生する金属塩化物による処理物の固着の問題を解消する観点より、上記の流通方向が好ましい。金属塩化物としては、ナトリウム、カルシウム、カリウム等の塩化物が特に問題となり易い。
【００３０】
具体的な流通経路は、まず、大気中、又は窒素ガスボンベ、窒素発生装置等のから供給されるガスを、内筒２０の排出部２２から導入して内筒２０の内部空間を流通させ、内筒２０の開口部２１を経由させて、内筒２０と外筒１１との間の空間を更に流通させ、外筒１１の導入部１１ａおよび供給管１２の導入口１２ａを経由させて加熱装置１０から排出させる。その後、バグフィルタ１６に供給して集塵した後、コンデンサ１７に供給して水銀等をドレンとして回収除去する。コンデンサ１７には冷却用の冷却水等が供給、排出される。コンデンサ１７の下流側には排気ファン１８が設けられ、吸引した排ガスは、大気放出せずに、例えば焼却炉又は集じん装置ＢＨなどに供給するのが好ましい。排ガスには微量のダイオキシン類や一酸化炭素などの未燃ガスが含まれるためである。
【００３１】
次に、本発明の焼却灰の処理装置について説明する。本発明の焼却灰の処理装置は、本発明の処理方法に好適に使用できるものであり、特に、処理物の炉壁への固着が生じにくく、処理物等の攪拌も良好に行える装置である。
【００３２】
本発明の処理装置は、図２に示すように、回転軸線Ｏがほぼ水平な外筒１１と、その内部に配設され外筒１１と略同一の回転軸線Ｏにて相対回転可能な内筒２０と、外筒１１の外周近傍に配置された加熱手段１４と、回転駆動手段３０とを備える。
【００３３】
外筒１１は、その一端に焼却灰の導入部１１ａを有し、他端が閉鎖されている。導入部１１ａにはシール部Ｓを介して供給管１２が接続され、供給管１２の上流側には灰の導入口１２ａが設けられている。外筒１１の導入部１１ａの近傍には回転支持のためのフランジ部１１ｂが設けられており、その部分から外筒１１の長手中央の位置までの外周面には保温材１３が設けられている。
【００３４】
外筒１１の他端は、環状部材で閉鎖され、その内側には保温材１１ｃが設けられている。環状部材には軸管１９が接続され、軸管１９が支持機構３３で回転自在に支持されている。この支持機構３３は軸受けが内装されており、内筒２０も回転自在に支持されている。また、軸管１９には、回転駆動のためのスプロケット１９ａが設けられている。
【００３５】
内筒２０は、外筒１１の他端の近傍に開口部２１を有し、他の端部に処理物の排出部２２を有する。また、排出部２２側には、外筒１１内部に配置される部分２０ａより径の小さい小径管部２０ｂが接続されている。
【００３６】
図２〜図４に示すように、内筒２０のうち外筒１１内部に配置される部分２０ａには、その外周面から外筒１１の内周面近傍まで立設しつつ軸線方向に沿って延びる複数（図の例では２枚）の仕切羽根２３が設けられている。仕切羽根２３は、外筒１１と内筒２０の間の空間を区分するように、外筒１１の両端付近まで延びている。この仕切羽根２３は平板である必要はなく、若干ねじれた形状であってもよい。
【００３７】
また、内筒２０には軸線方向に対して傾斜して開口部２１近傍まで配設される複数のガイド羽根２４，２５を有する。ガイド羽根２４，２５の端縁は部分的に外筒１１の内周面から離間しており、これにより仕切羽根２３で区分された複数の軸線方向空間の軸線方向の連通を許容する。ガイド羽根２４とガイド羽根２５の傾斜方向は複数（図の例では２つ）の軸線方向空間について略回転対称としてあり、これにより回転駆動手段３０により導入した焼却灰を他端側へ移送することができる。
【００３８】
つまり、矢印Ａ１の向きに内筒２０が回転する際、図３の紙面の裏側に焼却灰が位置する時は軸線方向の移動は殆ど起こらず、図３の紙面の表側に焼却灰が位置する時は、焼却灰がガイド羽根２４を伝って矢印Ａ２の向き（軸線方向に対して傾斜した方向）に落下（その際の転動攪拌効果が大きい）し、軸線方向の移動が起こり、その後の回転で落下した焼却灰が下流側のガイド羽根２４で同様にすくい取られて、順次軸線方向に移送される。従って、ガイド羽根２４の拡径部２４ａは、内筒２０の外周面から外筒１１の内周面近傍まで立設するのが好ましく、しかも仕切羽根２３との間に間隙を有しないのが好ましい。
【００３９】
本発明の処理装置では、内筒２０の内部に、開口部２１から導入した処理物を排出部２２へと移送する移送手段を有する。本実施形態では、この移送手段が、内筒２０の内部空間を複数に仕切る仕切壁３１と、その仕切壁３１で区分された複数の内部空間の軸線方向の連通を許容しつつ軸線方向に対して傾斜して配設される複数のガイド板２６，２７とを有する例を示す。ガイド板２６とガイド板２７の傾斜方向は複数（図の例では２つ）の内部空間について略回転対称としてあり、前述と同様の移送機構によって、内筒２０の回転により開口部２１より導入した処理物を排出部２２側へ移送することができる。
【００４０】
内筒２０の開口部２１側には、軸管２８が接続され、支持機構３３で外筒１１と共に支持されている。軸管２８と軸管１９との間はシール部Ｓを有する。この軸管２８には、熱伝対などのセンサ類を挿通することができ、更に同様に、仕切壁３１に挿通管を設けることも可能である。
【００４１】
一方、小径管部２０ｂの外周面には、スクリュー状の羽根３４を備え、供給管１２の導入口１２ａから供給された焼却灰は、内筒２０の回転によって、外筒１１側へと移送される。小径管部２０ｂの内部にも軸３６に形成されたスクリュー状の羽根３５を備え、外筒１１側から導入された処理物は、内筒２０の回転によって、排出部２２側へと移送される。供給管１２の外周には保温材が設けられていないため、排出部２２から排出される処理物の温度をより低温にするのに有利になる。逆に保温材１３を設けた部分では焼却灰の予熱温度を高める上で有利になる。
【００４２】
また、小径管部２０ｂには、回転駆動のためのスプロケット３７が設けられている。スプロケット３７の両側には、供給管１２とのシール部Ｓと取出部３８とのシール部Ｓとを有する。
【００４３】
加熱手段１４は、外筒１１の他端側の外周近傍に配置される。その際、外筒１１と固定して同時に回転させてもよいが、加熱の均一性を高める上で、回線させずに固定する方が好ましい。加熱手段１４はヒータ部１４ａ、内側保温材１４ｂ、外側保温材１４ｃなどで構成される。
【００４４】
回転駆動手段３０は、外筒１１と内筒２０とを異なる速度で回転させるものである。本実施形態では、外筒１１をスプロケット１９ａにより、また内筒２０をスプロケット３７により、電動モータ等でチェーン駆動することで、両者を回転駆動する。回転支持は、フランジ部１１ｂ、支持機構３３などで行っている。外筒１１と内筒２０との回転の速度差は、処理物の固着を防止する上で、内筒２０の回転速度の、１０〜５０％が好ましい。
【００４５】
内筒２０の排出部２２から排出された処理物は、取出部３８を経由して取り出される。取出部３８には流通ガスの導入口３９が設けられており、導入された流通ガスは、内筒２０の排出部２２から開口部２１を経て、外筒１１、供給管１２を経て焼却灰の導入口１２から排出される。
【００４６】
［他の実施形態］
以下、本発明の他の実施の形態について説明する。
【００４７】
（１）前述の実施形態では、本発明の処理方法を、内筒と外筒の間に前記被処理物の往路を備え、その内筒の内部に前記復路を備える横型回転加熱装置を用いて行う例を示したが、他の形式の横型回転加熱装置や回転加熱装置以外の装置も使用できる。
【００４８】
例えば、前記往路と復路との内外で逆転させたり、１重管の内部を２つの空間に仕切って各空間が往路と復路になるように、前述したガイド板を軸線方向に対して略同じ向きに傾斜させた回転加熱装置を用いてもよい。また、伝熱材で仕切られた往路と復路とに別個に逆方向の移送機構を設けたような非回転式の加熱装置を用いてもよい。
【００４９】
（２）前述の実施形態では、本発明の処理方法を、処理物の復路の後段側から被処理物の往路の前段側へと、流通ガスを流通させながら処理を行う例を示したが、ガスを流通させずに行ってもよく、また、流通ガスを循環させながら処理を行ってもよい。更に、内筒１１の軸管２８を介して流通ガスを導入し、焼却灰の往路と処理物の復路とに分けて流通させてもよい。
【００５０】
（３）前述の実施形態では、本発明の処理装置の移送手段が、内筒の内部空間を複数に仕切る仕切壁と複数のガイド板とで構成された例を示したが、回転体を別途内挿して独自の回転により移送するような移送手段としてもよい。例えば回転駆動させる回転軸にスクリュー状、又はプロペラ状の羽根を設けたもの等が挙げられる。
【００５１】
（４）その他、駆動機構、駆動源、回転支持機構、保温材、加熱手段、加熱源などは、同様の回転加熱装置に使用されるものがいずれも適用できる。
【００５２】
【実施例】
以下、本発明の構成と効果を具体的に示す実施例等について説明する。
【００５３】
実施例１
図１〜図４に示す処理装置を用い、原料温度：２０℃、原料投入量：１０ｋｇ／ｈｒ、パージガス：空気、パージガス流通量：５Ｎｍ³ ／ｈｒ、装置内の灰の平均滞留時間：１．０時間の条件で都市ごみ焼却処理施設のバグフィルタ捕集灰（ダイオキシン類の濃度は表１のとおり）を灰温度４０６〜４８３℃（ヒータ温度４００〜５５０℃）で加熱脱塩素化処理した。処理装置から約１２０℃で排出された処理物について、ガスクロマトグラフィー質量分析計によってＳＩＭ法で、ＰＣＤＤｓ，ＰＣＤＦｓを測定し、そのトータル量と毒性等価濃度とから各々について原料灰に対する分解率を求めた。その結果を表１に示す。
【００５４】
比較例１
実施例１において、加熱処理時の灰温度を３４４℃に変える以外は、全て同じ条件で加熱脱塩素化処理を行い、処理物について分解率を求めた。その結果を表１に示す。
【００５５】
【表１】

表１の結果が示すように、実施例１では４００〜５００℃の処理温度において、熱交換による冷却時の再合成も殆どなく、９７％以上の分解率が得られた。これに対して、３４４℃で加熱処理した比較例１では、分解率が約４０％になっており、加熱温度、流通ガス、滞留時間等を条件を考慮すると、熱交換による冷却時に再合成が生じたとために分解率が低下したと考えられる。
【００５６】
実施例２
実施例１において、ヒータ温度を５００℃に固定し、滞留時間を０．５〜３時間に変える以外は、実施例１と全て同じ条件で加熱脱塩素化処理を行い、処理物（排出時の温度１２０℃）について分解率を求めた。その結果を表２に示す。
【００５７】
【表２】

表２の結果が示すように、実施例２では、何れの条件でも熱交換による冷却時の再合成が殆どなく、高い分解率が得られ、特に１．０時間以上の滞留時間においては９９％以上の分解率が得られた。
【図面の簡単な説明】
【図１】本発明に用いる焼却灰の処理装置の一例を示す概略構成図
【図２】本発明の焼却灰の処理装置の一例を示す正面視断面図
【図３】本発明の焼却灰の処理装置の一例の要部を示す部分破断した斜視図
【図４】本発明の焼却灰の処理装置の一例の要部を示す側面視断面図
【図５】従来の焼却灰の処理装置を一部断面で示した正面図
【符号の説明】
１１外筒
１１ａ導入部
１４加熱手段
２０内筒
２１開口部
２２排出部
２３仕切羽根
２４ガイド羽根
２５ガイド羽根
２６ガイド板
２７ガイド板
３０回転駆動手段
３１仕切壁
Ｏ回転軸線[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for treating incineration ash (including dust collection fly ash, etc.) generated when incinerating municipal waste, industrial waste, etc., and an incineration ash treatment apparatus particularly suitable for the treatment, and is included in the incineration ash This is useful as a technique for reducing harmful organic chlorine compounds.
[0002]
[Prior art]
Organochlorine compounds that are harmful to the human body, such as highly toxic aromatic chlorinated compounds such as PCDD (polychlorinated dibenzodioxin) and PCDF (polychlorinated dibenzofuran), are used as secondary products during incineration. It is known to be produced and pollute the environment (K. Olieetal, Chemosphere, 6, 455 (1977), etc.). It has also been pointed out that the organochlorine compound is mixed in the incineration ash discharged from the electrostatic precipitator (EP) and other dust removing devices attached to the waste incineration facility. If incinerated ash contains PCDD, PCDF, or the like, for example, when the incinerated ash is used for landfill, there is a risk that it will return to the human body, animals and plants through leachate, etc. and adversely affect it.
[0003]
As a device for reducing the organic chlorine compounds in the incineration ash, a horizontal incineration ash heat dechlorination device having a screw rotation shaft, such as Japanese Patent Application Laid-Open No. 3-275184, is known. FIG. 5 is an explanatory diagram of such a conventional heat dechlorination treatment apparatus. This apparatus includes an apparatus main body 51 that is long in the horizontal direction, an incineration ash A inlet 52 and a discharge outlet 53 of the processed material that are provided at intervals in the axial direction of the apparatus main body 51, and the apparatus main body 51. The rotary shaft 56 is provided, an introduction portion screw 54, a stirring blade 57 and a discharge portion screw 55 fixed to the rotation shaft 56, and a band heater 58 disposed on the surface of the apparatus main body 51. Yes. The incineration ash A, which is the object to be treated, is introduced into the apparatus main body 51 from the incineration ash introduction port 52 and is moved in the direction of the discharge port 53 due to the action of the introduction portion screw 54 of the rotating shaft 56. While being stirred and mixed, the band heater 58 is heated to 300 ° C. or higher, for example, 400 ° C., and the organic chlorine compound contained in the incinerated ash A is decomposed. The treated product from which the organic chlorine compound has been decomposed and removed is extracted from the outlet 53 to the outside of the apparatus.
[0004]
JP-A-6-312172 discloses incineration ash collected from a waste incineration facility in a heating apparatus in order to provide a method and apparatus for incineration ash that can always obtain a high dechlorination rate stably. In the incineration ash treatment method for decomposing organochlorine compounds contained in the incineration ash by heating while moving, incineration while purging the inside of the heating device by forming an air flow opposite to the moving direction of the incineration ash A method for heating ash to 300 ° C. or higher is disclosed.
[0005]
[Problems to be solved by the invention]
However, when a heating device such as the above publication is used, it is necessary to preheat the incinerated ash that is the raw material, cool the processed material, etc., which is disadvantageous in terms of energy, and the entire facility is likely to be complicated and large. Moreover, when cooling a processed material under an air flow, unless temperature conditions etc. are controlled appropriately, there exists a problem that dioxins are re-synthesized from a decomposition product.
[0006]
On the other hand, JP-A-2001-25735 discloses a method for decomposing dioxins in ash in the presence of oxygen at 400 to 550 ° C., but when incineration ash is heat-treated at such a high temperature, In the processing apparatus as described in the above publication and a general rotary heating furnace, the difficulty of sticking the processed material to the furnace wall and stirring is likely to be a problem, and problems are likely to occur in terms of maintenance and processing efficiency. In other words, general dust collection fly ash has a high calcium chloride content, and further contains cadmium, lead, zinc, etc., so the melting point of fly ash is lower than the heating temperature, and the treated product adheres to the furnace wall, etc. Is likely to occur.
[0007]
Accordingly, an object of the present invention is to provide a method for treating incinerated ash that is advantageous in terms of energy, saves space, and is difficult to re-synthesize dioxins. It is another object of the present invention to provide an incineration ash treatment apparatus that can be suitably used in this treatment method, and that prevents the treated product from sticking to the furnace wall, and that can satisfactorily stir the treated product.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the inventors conceived to preheat incinerated ash by heat exchange in the heating device and cool the processed material, and even in that case, the heat treatment is performed at a temperature higher than usual. The present inventors have found that dioxins are less likely to be re-synthesized at the time of cooling the product, and have completed the present invention.
[0009]
That is, the incineration ash treatment method of the present invention is an incineration ash treatment method in which the incineration ash is decomposed by heating the incineration ash while moving the incineration ash in the heating device, and is partitioned by the heat transfer material. Equipped with outbound and return routes A horizontal rotary heating device having a forward path of the workpiece between the inner cylinder and the outer cylinder, and having the return path inside the inner cylinder, and rotating the outer cylinder and the inner cylinder at different speeds. Then, scrape the processed material adhering to the inner surface of the outer cylinder with the blades standing from the inner cylinder. After preheating the incinerated ash by heat exchange with the processed material in the region on the upstream side of the forward path using a heating device, the incinerated ash is added to the area on either the downstream side of the forward path or the upstream side of the return path. It heats at -500 degreeC, Then, the processed material is cooled by heat exchange with incinerated ash in the area | region of the back | latter stage of the said return path, It is characterized by the above-mentioned.
[0011]
Further, it is preferable to perform the treatment while circulating air, an inert gas, or a mixed gas thereof from the rear stage side of the return path to the front stage side of the forward path.
[0012]
On the other hand, the incineration ash treatment apparatus of the present invention has an incineration ash introduction part at one end and an outer cylinder whose rotation axis is almost horizontal with the other end closed, and an opening near the other end. An inner cylinder that is relatively rotatable about the same rotation axis as the outer cylinder having a processed product discharge portion at an end of the outer cylinder, a heating means disposed near the outer periphery of the other end of the outer cylinder, and the outer cylinder An incineration ash treatment apparatus comprising a rotation driving means capable of rotating a cylinder and the inner cylinder at different speeds, wherein the inner cylinder stands from its outer peripheral surface to the vicinity of the inner peripheral surface of the outer cylinder. A plurality of partitioning blades extending along the axial direction and a plurality of axial spaces partitioned by the partitioning blades are disposed up to the vicinity of the opening while being inclined with respect to the axial direction while allowing communication in the axial direction. A plurality of guide vanes, and the inclination direction of the guide vanes is substantially rotated about the plurality of axial spaces. The ash introduced by the rotary drive means as the symmetric and can be transferred to the other end side, in the interior of the inner cylinder, having a transfer means for transferring the treated product is introduced from the opening to the discharge section.
[0013]
In the above, the transfer means is inclined with respect to the axial direction while permitting communication in the axial direction between the partition wall partitioning the inner space of the inner cylinder into a plurality of spaces and the plurality of internal spaces partitioned by the partition wall. A plurality of guide plates disposed, and a treatment product introduced from the opening by rotation of the inner cylinder, with the inclined direction of the guide plates being substantially rotationally symmetric with respect to the plurality of internal spaces, toward the discharge portion. It is preferable to be transportable.
[0014]
[Function and effect]
According to the method for treating incineration ash of the present invention, the incineration ash is obtained by exchanging heat with the treated product in a region on the upstream side of the forward path using a heating device having a forward path and a return path of the object to be treated partitioned by a heat transfer material. The incinerated ash is heat-treated in any region on the downstream side of the forward path and the upstream side of the return path, and then the processed product is subjected to heat exchange with the incinerated ash in the area on the downstream side of the return path. Since it cools, the preheating of the incinerated ash which is a raw material, the cooling of a processed material, etc. become unnecessary. Moreover, since heat processing is performed at 400-500 degreeC, as the result of an Example shows, even if a processed material is cooled slowly at the time of cooling, it becomes difficult to re-synthesize dioxins. As a result, it is possible to provide a method for treating incinerated ash that is advantageous in terms of energy, saves space, and is difficult to re-synthesize dioxins.
[0015]
The heating device is a horizontal rotary heating device that includes a forward path of the object to be processed between an inner cylinder and an outer cylinder and includes the return path inside the inner cylinder, and the outer cylinder and the inner cylinder are moved at different speeds. When rotating and scraping the processed material adhering to the inner surface of the outer cylinder with the blades standing from the inner cylinder, the heat of the processed material moving in the return path inside the inner cylinder transfers heat to the incineration ash moving in the surrounding forward path In doing so, there is little heat loss and the preheating of the incinerated ash and the cooling of the treated product can be performed efficiently. Moreover, the problem of sticking of a processed material can be solved by scraping the processed material adhering to the inner surface of the outer tube with a blade standing from the inner tube.
[0016]
When the treatment is performed while circulating air or an inert gas or a mixed gas thereof from the rear stage side of the return path to the front stage side of the forward path, the trace component of the generated metal chloride is in contact with the processed material in a high temperature state. Therefore, it is difficult to cause a melting point drop due to the condensation, and it is difficult for the processed material to adhere to the apparatus wall surface.
[0017]
On the other hand, according to the incineration ash treatment apparatus of the present invention, the partition blades are divided by the partition blades extending along the axial direction while standing from the outer peripheral surface of the inner tube to the vicinity of the inner peripheral surface of the outer tube. A plurality of guide blades that are inclined to the axial direction while allowing the communication in the axial direction of the plurality of axial spaces, and are arranged to the vicinity of the opening, and the inclination direction of the guide blades Since the axial space is substantially rotationally symmetric, the incinerated ash introduced by the rotation driving means can be transferred to the other end side while stirring and rolling. And since the heating means is disposed in the vicinity of the outer periphery on the other end side of the outer cylinder, the organic chlorine compound contained in the incinerated ash is decomposed on the other end side of the outer cylinder and the inner cylinder in the vicinity thereof. Can do. Further, since the inside cylinder has a transfer means for transferring the processed material introduced from the opening to the discharge portion, heat exchange between the high-temperature processed material transferred to the discharge portion and the raw material incineration ash is performed. Can be efficiently performed via the inner cylinder. Further, the inner cylinder having partition blades standing up to the vicinity of the inner peripheral surface of the outer cylinder can be rotated relative to the outer cylinder, and includes rotational drive means that can rotate both at different speeds. Adherence can be suitably scraped off by the partition blades from the inner peripheral surface of the outer cylinder where adhesion is likely to be a problem. As a result, it is possible to provide an incineration ash treatment apparatus that can be suitably used in the treatment method of the present invention, and that the treated product is less likely to stick to the furnace wall, and that the treated product can be well stirred.
[0018]
The transfer means is arranged to be inclined with respect to the axial direction while allowing the partition wall partitioning the inner space of the inner cylinder into a plurality and the plurality of inner spaces partitioned by the partition wall in the axial direction. A plurality of guide plates, and the treatment product introduced from the opening by rotation of the inner cylinder with the inclined direction of the guide plates being substantially rotationally symmetric with respect to the plurality of internal spaces can be transferred to the discharge portion side. In this case, the processed product can be transferred to the discharge portion side while stirring and rolling only by rotating the inner cylinder by the partition wall and the guide plate. Therefore, it is not necessary to separately provide a rotating body and its driving means inside the inner cylinder, and maintenance and space saving can be further improved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration diagram of an example of a processing apparatus of the present invention. In addition, the broken line in a figure shows the flow of gas, and the continuous line has shown solid flows, such as incineration ash.
[0020]
The incineration ash treatment method of the present invention includes a heating device having a forward path and a return path of an object to be treated partitioned by a heat transfer material, and is heated while moving the incineration ash in the heating apparatus and is included in the incineration ash It decomposes organic chlorine compounds. In the present embodiment, as shown in FIG. 1, the heating apparatus 10 includes a forward rotation path for the workpiece between the inner cylinder 20 and the outer cylinder 11, and a horizontal rotation including a return path for the workpiece within the inner cylinder 20. An example of a heating device that performs processing while circulating a gas such as air from the rear side of the return path to the front side of the forward path will be described.
[0021]
In the treatment method of the present invention, first, the incinerated ash is preheated by heat exchange with the treated product in the region on the upstream side of the forward path. As the incineration ash used, incineration ash (including dust collection fly ash) generated when incineration of general waste such as municipal waste or industrial waste can be used. The incinerated ash is stored in, for example, the storage hopper 1 and a predetermined amount is supplied from the introduction port 12a of the heating device 10 by the quantitative cutting device. The supplied incineration ash moves the supply pipe 12 to the outer cylinder 11 side, and further moves to the other end side of the outer cylinder 11 through the introduction part 11a of the outer cylinder 11. Incineration ash can be preheated by exchanging heat with the processed material moving inside the inner cylinder 20 in the region on the upstream side of such a forward path. In addition, you may coat | cover the area | region which performs heat exchange with the heat insulating material 13. FIG.
[0022]
Next, the incinerated ash is heated at 400 to 500 ° C. in any region on the downstream side of the forward path and the upstream side of the backward path. By the heat treatment, the decomposition rate of dioxins can be 95% or more. When the heating temperature is less than 400 ° C., the dioxins are easily re-synthesized when the treated product is gradually cooled during cooling. Further, when the temperature exceeds 500 ° C., the processed product is likely to be melted and fixed, which is disadvantageous in terms of energy.
[0023]
Heating can be performed by the heating means 14 disposed in the vicinity of the outer periphery of the outer cylinder 11. As the heating means 14, an electric heater, a combustion type heater, a gas supply heater, or the like can be used, but an electric heater is preferable for simplifying and downsizing the entire facility. Moreover, it is preferable to provide the heat insulating material 15 also around the part formed by the heating means 14.
[0024]
The incinerated ash is moved to the other end side of the outer cylinder 11 while being heated by the heating means 14, then moved to the inside from the opening 21 of the inner cylinder 20, and further heated to the discharge section 22 side of the inner cylinder 20. Moving.
[0025]
The processed product after heating is cooled by heat exchange with the incinerated ash in a region on the rear stage of the return path. The preheating of the incinerated ash and the cooling of the processed product by heat exchange are preferably performed so that the temperature difference between the raw material incinerated ash and the discharged processed product is within 200 ° C, more preferably within 100 ° C. Moreover, it is preferable that the temperature of the discharged processed product after cooling is 250 ° C. or lower, and more preferably 200 ° C. or lower. The amount of heat exchanged can be determined by the throughput, residence time, heat transfer area, and the like.
[0026]
In the present embodiment, the inner cylinder 20 serves as a heat transfer material that partitions the forward path and the return path. As such a heat transfer material, a metal material, ceramics, or the like can be used, and a metal material is particularly preferable from the viewpoint of workability. Moreover, since the stirring blade etc. formed in the outer peripheral surface or inner peripheral surface of the inner cylinder 20 also have a heat transfer function, it is preferable to be comprised with the same heat-transfer material.
[0027]
The processed material after pre-cooling is discharged from the discharge portion 22 of the inner cylinder 20. The processed product discharged from the inner cylinder 20 is stored at one end or continuously discharged outside the system. However, in the present invention, sufficient cooling can be performed, so that an additional cooling device may be unnecessary. Is possible. Depending on the conditions, it is also possible to reduce the energy consumption (for example, power consumption) to 1/2 to 1/3 as compared with a conventional incinerator ash treatment apparatus that does not perform heat exchange. As a temperature profile of the incineration ash in the processing method of the present invention, for example, when the set temperature of the heating means 14 is set to 500 ° C., the incineration ash in the introduction part 11a of the outer cylinder 11 is about 90 ° C., and the heating means 14 of the outer cylinder 11 About 230 ° C. just before the inside, about 430 ° C. near the opening 21 of the inner cylinder 20, about 330 ° C. just after the inside of the heating means 14 of the inner cylinder 20, and about 120 ° C. inside the inner cylinder 20 near the introduction portion 11a. It is. In addition, according to the processing method of the present invention, for example, 100 to 1000 kg of incinerated ash can be processed.
[0028]
In the present embodiment, the treatment is performed while air, an inert gas, or a mixed gas thereof is circulated from the downstream side of the return path of the incineration ash to the upstream side of the forward path. The circulating gas is most preferably air from the viewpoint of cost and the like.
[0029]
Although the direction of the flow gas may be the reverse direction, the flow direction described above is preferable from the viewpoint of solving the problem of the sticking of the processed material due to the metal chloride generated as described above. As metal chlorides, chlorides such as sodium, calcium and potassium are particularly problematic.
[0030]
Specifically, first, a gas supplied from the atmosphere or a nitrogen gas cylinder, a nitrogen generator, or the like is introduced from the discharge portion 22 of the inner cylinder 20 to circulate the inner space of the inner cylinder 20. The space between the inner cylinder 20 and the outer cylinder 11 is further circulated through the opening 21 of the cylinder 20, and the heating device 10 is transmitted via the introduction portion 11 a of the outer cylinder 11 and the inlet 12 a of the supply pipe 12. To drain. Thereafter, the dust is supplied to the bag filter 16 and collected, and then supplied to the capacitor 17 to collect and remove mercury or the like as a drain. Cooling water or the like for cooling is supplied to and discharged from the capacitor 17. An exhaust fan 18 is provided on the downstream side of the condenser 17, and the sucked exhaust gas is not released into the atmosphere, for example, an incinerator or Collection It is preferable to supply to the dust device BH or the like. This is because the exhaust gas contains a small amount of unburned gas such as dioxins and carbon monoxide.
[0031]
Next, the incineration ash treatment apparatus of the present invention will be described. The incineration ash processing apparatus of the present invention can be suitably used in the processing method of the present invention, and in particular, is an apparatus that hardly adheres to the furnace wall of the processed product and can satisfactorily stir the processed product. .
[0032]
As shown in FIG. 2, the processing apparatus according to the present invention includes an outer cylinder 11 having a rotation axis O that is substantially horizontal, and an inner cylinder that is disposed within the outer cylinder 11 and is relatively rotatable about the rotation axis O that is substantially the same as the outer cylinder 11. 20, a heating unit 14 disposed near the outer periphery of the outer cylinder 11, and a rotation driving unit 30.
[0033]
The outer cylinder 11 has an incineration ash introduction part 11a at one end, and the other end is closed. A supply pipe 12 is connected to the introduction part 11a via a seal part S, and an ash introduction port 12a is provided on the upstream side of the supply pipe 12. A flange portion 11b for rotation support is provided in the vicinity of the introduction portion 11a of the outer cylinder 11, and a heat insulating material 13 is provided on the outer peripheral surface from the portion to the position of the longitudinal center of the outer cylinder 11. .
[0034]
The other end of the outer cylinder 11 is closed with an annular member, and a heat insulating material 11c is provided inside thereof. A shaft tube 19 is connected to the annular member, and the shaft tube 19 is rotatably supported by a support mechanism 33. The support mechanism 33 is provided with a bearing, and the inner cylinder 20 is also rotatably supported. The shaft tube 19 is provided with a sprocket 19a for rotational driving.
[0035]
The inner cylinder 20 has an opening 21 in the vicinity of the other end of the outer cylinder 11, and a processed product discharge section 22 at the other end. Further, a small-diameter pipe portion 20b having a smaller diameter than the portion 20a disposed inside the outer cylinder 11 is connected to the discharge portion 22 side.
[0036]
As shown in FIGS. 2 to 4, a portion 20 a of the inner cylinder 20 that is disposed inside the outer cylinder 11 extends along the axial direction while standing from the outer peripheral surface to the vicinity of the inner peripheral surface of the outer cylinder 11. A plurality of (two in the illustrated example) partition blades 23 are provided. The partition blades 23 extend to the vicinity of both ends of the outer cylinder 11 so as to partition the space between the outer cylinder 11 and the inner cylinder 20. This partition blade 23 does not need to be a flat plate, and may have a slightly twisted shape.
[0037]
In addition, the inner cylinder 20 has a plurality of

guide blades

24 and 25 which are inclined with respect to the axial direction and arranged to the vicinity of the opening 21. The end edges of the

guide vanes

24 and 25 are partially separated from the inner peripheral surface of the outer cylinder 11, thereby permitting communication in the axial direction of a plurality of axial spaces divided by the partition vanes 23. The inclination directions of the guide blade 24 and the guide blade 25 are substantially rotationally symmetric with respect to a plurality of (two in the illustrated example) axial space, thereby transferring the incinerated ash introduced by the rotation driving means 30 to the other end side. Can do.
[0038]
That is, when the inner cylinder 20 rotates in the direction of the arrow A1, when the incineration ash is located on the back side of the paper surface of FIG. 3, the axial movement hardly occurs, and the incineration ash is located on the front side of the paper surface of FIG. When the incineration ash travels along the guide blade 24 and falls in the direction of the arrow A2 (inclined with respect to the axial direction) (the rolling agitation effect at that time is large), the movement in the axial direction occurs. The incinerated ash that has fallen by rotation is similarly picked up by the guide blades 24 on the downstream side and sequentially transferred in the axial direction. Therefore, the enlarged diameter portion 24a of the guide blade 24 is preferably erected from the outer peripheral surface of the inner cylinder 20 to the vicinity of the inner peripheral surface of the outer cylinder 11, and it is preferable that there is no gap between the guide blade 24 and the partition blade 23. .
[0039]
In the processing apparatus of the present invention, the inner cylinder 20 has a transfer means for transferring the processed material introduced from the opening 21 to the discharge portion 22. In the present embodiment, the transfer means allows a partition wall 31 that partitions the inner space of the inner cylinder 20 into a plurality of spaces, and a plurality of inner spaces partitioned by the partition walls 31 while allowing communication in the axial direction. The example which has the some

guide plates

26 and 27 arrange | positioned inclined is shown. The inclination directions of the guide plate 26 and the guide plate 27 are substantially rotationally symmetric with respect to a plurality (two in the example shown in the figure) of the internal space, and are introduced from the opening 21 by the rotation of the inner cylinder 20 by the same transfer mechanism as described above. The processed product can be transferred to the discharge unit 22 side.
[0040]
A shaft tube 28 is connected to the opening 21 side of the inner cylinder 20 and is supported together with the outer cylinder 11 by a support mechanism 33. A seal portion S is provided between the shaft tube 28 and the shaft tube 19. Sensors such as thermocouples can be inserted into the shaft tube 28, and similarly, an insertion tube can be provided on the partition wall 31.
[0041]
On the other hand, a screw-shaped blade 34 is provided on the outer peripheral surface of the small-diameter pipe portion 20b, and the incineration ash supplied from the inlet 12a of the supply pipe 12 is transferred to the outer cylinder 11 side by the rotation of the inner cylinder 20. The A screw-like blade 35 formed on the shaft 36 is also provided inside the small-diameter pipe portion 20b, and the processed material introduced from the outer cylinder 11 side is transferred to the discharge section 22 side by the rotation of the inner cylinder 20. . Since the heat insulating material is not provided on the outer periphery of the supply pipe 12, it is advantageous to make the temperature of the processed material discharged from the discharge portion 22 lower. On the contrary, the portion provided with the heat insulating material 13 is advantageous in increasing the preheating temperature of the incinerated ash.
[0042]
Further, the small diameter pipe portion 20b is provided with a sprocket 37 for rotational driving. On both sides of the sprocket 37, a seal portion S with the supply pipe 12 and a seal portion S with the take-out portion 38 are provided.
[0043]
The heating means 14 is disposed near the outer periphery on the other end side of the outer cylinder 11. At that time, it may be fixed to the outer cylinder 11 and rotated at the same time. However, in order to improve the uniformity of heating, it is preferable to fix it without using a line. The heating means 14 includes a heater portion 14a, an inner heat insulating material 14b, an outer heat insulating material 14c, and the like.
[0044]
The rotation drive means 30 rotates the outer cylinder 11 and the inner cylinder 20 at different speeds. In the present embodiment, the outer cylinder 11 is driven by a sprocket 19a, and the inner cylinder 20 is driven by a sprocket 37 by an electric motor or the like, so that both are rotationally driven. The rotation support is performed by the flange portion 11b, the support mechanism 33, and the like. The rotation speed difference between the outer cylinder 11 and the inner cylinder 20 is preferably 10 to 50% of the rotation speed of the inner cylinder 20 in order to prevent the processed material from sticking.
[0045]
The processed product discharged from the discharge portion 22 of the inner cylinder 20 is taken out via the take-out portion 38. The extraction portion 38 is provided with a circulation gas inlet 39, and the introduced circulation gas passes through the opening portion 21 from the discharge portion 22 of the inner cylinder 20, passes through the outer cylinder 11 and the supply pipe 12, and is incinerated ash. It is discharged from the inlet 12.
[0046]
[Other Embodiments]
Hereinafter, other embodiments of the present invention will be described.
[0047]
(1) In the above-described embodiment, the processing method of the present invention is performed using a horizontal rotary heating apparatus that includes the forward path of the workpiece between the inner cylinder and the outer cylinder, and includes the return path inside the inner cylinder. Although the example which performs is shown, apparatuses other than a horizontal type | mold rotary heating apparatus and rotary heating apparatus of another type can also be used.
[0048]
For example, the guide plate described above is arranged in substantially the same direction with respect to the axial direction so as to reverse the inside and outside of the forward path and the return path, or to partition the inside of the single pipe into two spaces and each space becomes the forward path and the return path. You may use the rotating heating apparatus inclined in the direction. Moreover, you may use the non-rotation type heating apparatus which provided the transfer mechanism of the reverse direction separately in the outward path | route and the backward path | route partitioned with the heat-transfer material.
[0049]
(2) In the above-described embodiment, the processing method of the present invention has been described with reference to an example in which the processing gas is circulated from the downstream side of the return path of the processed material to the upstream side of the outbound path of the workpiece. The treatment may be performed without circulating the gas, or the treatment may be performed while circulating the circulating gas. Furthermore, a circulation gas may be introduced through the shaft tube 28 of the inner cylinder 11 and distributed separately for the incineration ash outbound path and the treated product return path.
[0050]
(3) In the above-described embodiment, the example in which the transfer unit of the processing apparatus of the present invention is configured by the partition wall that partitions the inner space of the inner cylinder into a plurality and a plurality of guide plates has been described. It is good also as a transfer means which interpolates and transfers by original rotation. For example, the thing which provided the screw-like or propeller-like blade | wing on the rotating shaft to rotate is mentioned.
[0051]
(4) In addition, any drive mechanism, drive source, rotation support mechanism, heat insulating material, heating means, heating source, etc. that are used in the same rotation heating apparatus can be applied.
[0052]
【Example】
Examples and the like specifically showing the configuration and effects of the present invention will be described below.
[0053]
Example 1
1 to 4, raw material temperature: 20 ° C., raw material input amount: 10 kg / hr, purge gas: air, purge gas flow rate: 5 Nm ^Three / Hr, average residence time of ash in the equipment: Bag filter collected ash (dioxin concentration is as shown in Table 1) of municipal waste incineration facility under the condition of 1.0 hour. Heat dechlorination treatment was performed at a temperature of 400 to 550 ° C. PCDDs and PCDFs are measured by SIM method using a gas chromatography mass spectrometer for the processed product discharged at about 120 ° C from the processing equipment, and the decomposition rate for raw ash is determined for each from the total amount and the toxic equivalent concentration. It was. The results are shown in Table 1.
[0054]
Comparative Example 1
In Example 1, except that the ash temperature during the heat treatment was changed to 344 ° C., the heat dechlorination treatment was performed under the same conditions, and the decomposition rate was obtained for the treated product. The results are shown in Table 1.
[0055]
[Table 1]

As shown in the results of Table 1, in Example 1, at a treatment temperature of 400 to 500 ° C., there was almost no resynthesis during cooling by heat exchange, and a decomposition rate of 97% or more was obtained. On the other hand, in Comparative Example 1 heat-treated at 344 ° C., the decomposition rate is about 40%, and when the heating temperature, flow gas, residence time, etc. are taken into consideration, resynthesis is possible during cooling by heat exchange. It is thought that the decomposition rate decreased because it occurred.
[0056]
Example 2
In Example 1, except that the heater temperature is fixed at 500 ° C. and the residence time is changed to 0.5 to 3 hours, the heat dechlorination treatment is performed under the same conditions as in Example 1, and the processed product (at the time of discharge) The decomposition rate was determined for a temperature of 120 ° C. The results are shown in Table 2.
[0057]
[Table 2]

As shown in the results of Table 2, in Example 2, there was almost no resynthesis during cooling by heat exchange under any conditions, and a high decomposition rate was obtained, especially 99% in a residence time of 1.0 hour or more. The above decomposition rate was obtained.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an example of an incineration ash treatment apparatus used in the present invention.
FIG. 2 is a front sectional view showing an example of the incineration ash treatment apparatus of the present invention.
FIG. 3 is a partially broken perspective view showing a main part of an example of the incineration ash treatment apparatus of the present invention.
FIG. 4 is a side cross-sectional view showing the main part of an example of the incineration ash treatment apparatus of the present invention
FIG. 5 is a front view of a conventional incineration ash treatment apparatus partially shown in cross section.
[Explanation of symbols]
11 outer cylinder
11a Introduction
14 Heating means
20 inner cylinder
21 opening
22 Discharge section
23 partition blade
24 guide vanes
25 guide vanes
26 Guide plate
27 Guide plate
30 Rotation drive means
31 partition wall
O rotation axis

Claims

In the incineration ash treatment method of decomposing organochlorine compounds contained in the incineration ash by heating while moving the incineration ash in the heating device,
Forward and reverse passes of Bei Eteori of the workpiece partitioned by the heat transfer material, comprising a forward path of the object to be treated between the inner cylinder and the outer cylinder, horizontal rotary heating device comprising the return to the inside of the inner cylinder Using a heating device that rotates the outer cylinder and the inner cylinder at different speeds, and scrapes the processed material adhering to the inner surface of the outer cylinder with blades standing from the inner cylinder ,
After preheating the incineration ash by heat exchange with the processed material in the area on the front side of the forward path, the incineration ash is heated at 400 to 500 ° C. in any area on the rear stage side of the forward path and the front stage side of the return path. Then, the treated product is cooled by heat exchange with the incinerated ash in a region on the downstream side of the return path, and a method for treating the incinerated ash is provided.

The method for treating incineration ash according to claim 1, wherein the treatment is performed while air, an inert gas, or a mixed gas thereof is circulated from a rear stage of the return path to a front stage of the forward path.

An outer cylinder in which an incineration ash introduction part is provided at one end and the other end is closed and the rotation axis is substantially horizontal, and an opening is provided in the vicinity of the other end, and a discharge part for processed material is provided at the other end. The inner cylinder that can rotate relative to the outer cylinder at substantially the same rotation axis, the heating means disposed near the outer periphery of the other end of the outer cylinder, and the outer cylinder and the inner cylinder can be rotated at different speeds. An incineration ash treatment device comprising a rotational drive means,
The inner cylinder has a plurality of partition blades extending in the axial direction while standing up from the outer peripheral surface to the vicinity of the inner peripheral surface of the outer cylinder, and an axial direction of a plurality of axial spaces divided by the partition blades. A plurality of guide blades that are inclined to the axial direction while allowing communication, and are arranged to the vicinity of the opening, and the inclination direction of the guide blades is substantially rotationally symmetric with respect to the plurality of axial spaces. The incineration ash treatment apparatus having transfer means for transferring the incinerated ash introduced by the rotation driving means to the other end side, and transferring the processed material introduced from the opening to the discharge portion inside the inner cylinder. .

The transfer means is arranged to be inclined with respect to the axial direction while allowing the partition wall partitioning the inner space of the inner cylinder into a plurality and the plurality of inner spaces partitioned by the partition wall in the axial direction. A plurality of guide plates, and the treatment product introduced from the opening by rotation of the inner cylinder with the inclined direction of the guide plates being substantially rotationally symmetric with respect to the plurality of internal spaces can be transferred to the discharge portion side. The incineration ash processing apparatus according to claim 3.